Lubricating oil containing an hydroxylated amine and an overbased sulfonate or phenate

ABSTRACT

POLY(HYDROXYALKYLATED) AMINES ARE COMBINED ARE COMBINED WITH ALKALINE EARTH METAL CARBONATES DISPERSED IN A HYDROCARBON MEDIUM TO PROVIDE IMPROVED RUST PROTECTION IN INTERNAL COMBUSTION ENGINES.

United States Patent Ofi Fice 3,711,406 Patented Jan. 16, 1973 3,711,406 LUBRICATING OIL CONTAINING AN HYDROX- YLATED AMHNE AN l) AN OVERBASED SULFONATE OR PHENATE Warren Lowe, El Cerrito, Califi, assignor to Chevron Research Company, San Francisco, Calif. No Drawing. Filed June 11, 1970, Ser. No. 45,567 Int. Cl. Cm 1/20, 1/32, 1/40 US. Cl. 25233.4 8 Claims ABSTRACT OF THE DISCLOSURE Poly(hydroxyalkylated) amines are combined with alkaline earth metal carbonates dispersed in a hydrocarbon medium to provide improved rust protection in internal combustion engines.

BACKGROUND OF THE INVENTION Field of the invention Lubricating oils are employed not only for lubrication, but as a vehicle to promote a wide variety of protection for the surfaces lubricated by the oil. The tendency for rusting has required that lubricating oils include additives which inhibit rust. Also included in lubricating oils for internal combustion engines are bases capable of neutralizing the acids which are formed during fuel combustion, and by blow-by or other mechanisms which are introduced into the oil.

Description of the prior art In US. Pat. No. 3,458,444 alkenyl succinates of hydrocarbon-substituted ethanolamines are taught as rust inhibitors. Various alkanolamines are taught in US. Pats. Nos. 3,197,510 and 3,398,197, the compounds having a wide variety of uses.

SUMMARY Poly(hydroxyalkylated) alkyl-substituted amines in combination with alkaline earth metal carbonates dispersed in a hydrocarbon lubricating oil medium are combined to provide rust protection, corrosion protection and acid neutralization. The carbonate will be present in the oil to provide an alkalinity value of at least 0.5 mg. KOH/ g. while the amine will be present in at least 0.05 weight percent.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS The compositions of this invention are a combination of a hydroxyalkylated alkyl-substituted amine and an alkaline earth metal carbonate in a hydrocarbon oil of lubricating viscosity. The composition provides enhanced rust and corrosion protection. Other additives may also be included to fulfill functions other than those provided for by the base and hydroxyalkylated amine, as Well as to augment the functions of the aforementioned additives.

The hydroxyalkylated amines will be present in at least 0.05 weight percent and not greater than about 3 weight percent in compositions in use in internal combustion engines. More usually, the hydroxyalkylated amine will be present in from about 0.1 to 2 Weight percent and preferably from about 0.2 to 1 Weight percent.

The alkaline earth metal carbonate will normally be present to provide alkalinity values of from about 0.5 to mg. KOH/g, more usually from about 1 to 20 mg. KOH/g., (for method of determination, see Abbott & Farley, Methods and Significance of Base Determination in Marine Cylinder Lubrication Oils, 23rd ASLE Meeting, May, 1968). While alkalinity values in excess of 10 mg. KOH/ g. are not essential to rusting protection, values in excess of 10 mg. KOH/ g. will frequently be used for a particular service. In marine lubrication, alkalinity values are high, while in automobile lubrication, alkylinity values are relatively low.

Other additives will be present in varying amounts, the total amount or" other additives normally not exceeding 15 weight percent and usually not being less than 0.1 weight percent. These additives include ashless dispersants such as succinimides, hydrocarbyl alkylene polyamines, etc., dithiophosphates, carboxylic acid corrsion inhibitors, etc.

COMPONENTS Hydoxyalkylated amines The hydroxalkylated alkal-substituted amine will have the following formula:

wherein a is 0 or 1;

U is alkylene of from 2 to 3 carbon atoms, preferably 2 carbon atoms, there being at least 2 carbon atoms between nitrogen and oxygen;

Y is alkylene of from 2 to 3 carbon atoms, preferably 3 carbon atoms, there being at least 2 carbon atoms between the nitrogen atoms; and

R is an aliphatic hydrocarbon group of from 12 to 24 carbon atoms, either straight chain or branched chain, preferably straight chain, having from 0 to 2 sites of aliphatic unsaturation, usually ethylenic, preferably 0 to 1 site of ethylenic unsaturation. R may be a single alkyl group or a mixture of alkyl groups substantially all of the alkyl groups falling within the specified carbon range. Preferalby, R is alkyl or alkenyl of from 16 to 18 carbon atoms and particularly preferred 18 carbon atoms. The R groups may be derived from synthetic or natural sources.

Illustrative alkyl groups are derived from tallow amines, oleyl amine, stearyl amine, lauryl amine, behenyl amine, etc.

Illustrative compounds which fined use within the scope of this invention are N,N,N'-tri(Z-hydroxyethyl) N-octadecyl propylene diamine, N,N',N'-t'ri(Z-hydroxyethyl) N- octadecenyl propylene diamine, 'N,N,N-tri(2-hydroxyethyl) Nhexadecyl propylene diamine, N,N',N-tri(3 hydroxypropyl) N-octadecadienyl propylene diamine, N, N',N'-tri(Z-hydroxyethyl) N-octadecyl ethylene diamine, N,N,N'-tri(2-hydroxyethyl) N-octadecenyl ethylene diamine, N,N,N-tri(Z-hydroxyethyl) N-tetradecyl propyle'ne diamine, 'N,N-di(2-hydroxyethyl) oleyl amine, N,N-di- (Z-hydroxyethyl) stearyl amine, N,N-di(3-hydroxypropyl) tetradecylamine, N,N-di(2-hydroxyethyl) octadecenyl amine, N,N-di(2-hydroxyethyl) eicosyl amine, etc.

The monoand diamines may be used individually or as mixtures. Mixtures may vary from to 90 weight percent of either monoor diamines.

Alkaline earth metal carbonates The alkaline earth metal carbonates are magnesium, calcium and barium carbonates, preferably calcium and barium carbonates. Small amounts of the hydroxides of the metals may also be present, usually not contributing more than about 20% of the alkalinity value from the alkaline earth metal carbonate composition. The alkaline earth metals are not soluble in hydrocarbon media. Therefore, they are invariably dispersed with some type of metal salt dispersant. These dispersants are well known in the art and will be discussed only summarily.

The preferred dispersants are the sulfonate and phenate dispersants. The sulfonates are extensively discussed in U.S. Pat. No. 3,488,284. The organic sulfonates are pre pared either from natural or synthetic sources. The natural sulfonates are referred to as mahogany sulfonates and are derived from petroleum mineral oil fractions and normally have from about 25 to 50 carbon atoms per sulfonic acid. Synthetic sources are also employed which are usual- 1y alkylated benzenes having from about 25 to 50 carbon atoms. The use of the sulfonates and the method of preparing overbased sulfonates is well known, as already indicated by the above patent. Other patents include U.S. Pats. Nos. 3,021,280, 3,256,186, 3,057,896 and 3,312,618.

Another class of dispersant for alkaline earth metal carbonates are the phenates. The phenates are alkyl-ated phenols either individually or polymerized to a low order of from 2 to '5 alkyl phenols, normally bridged with sulfur, alkylene groups, or di(alkylene) amino groups (Mannich bases). The alkyl group on the phenol is normally of at least 8 carbons and usually does not exceed 36 carbon atoms, more usually being in the range of about 12 to 30 carbon atoms. The phenoxide in the phenate also contributes to alkalinity value.

The overbased phenates are described in numerous patents such as U.S. Pats. Nos. 3,474,035, 3,429,812, 3,388,063, 3,336,224 and 2,798,852.

Other dispersants which are also employed are the alkaline earth metal alkyl phosphonates and thiophosphonates. The phosphonates will normally be at least about 30 carbon atoms and may be as high as 200 carbon atoms, more usually from about 50 to 125 carbon atoms. These overbased phosphonates are described in U.S. Pat. No. 3,312,618.

Another group of dispersants are the succinimides of alkylene polyarnines. These dispersants usually have an alkyl or alkenyl group bonded to the succinimide group of at least 50 carbon atoms and not more than about 200 carbon atoms. The alkylene polyamines are normally ethylene or propylene polyamines having from 2 to 6 amino groups, more usually from 3 to 5 amino groups. Carboxylates also find use as dispersants.

The alkalinity value of the overbased dispersants will usually be at least 150 and not exceed 500, more usually being in the range of about 200 to 450 mg. K-OH/ g. The equivalent ratio of base to dispersant will be at least 1 to 1 and more usually at least 1.5 to 1, normally not exceeding about 20 to 1.

These compositions are used in a sufficient amount to provide the desired alkalinity value in the final composition. Therefore, the alkaline earth metal carbonates are prepared as concentrates and then diluted in the lubricating oil medium with the hydroxyalkylated amine to provide the desired end composition.

Lubricating oils The oils which find use in this invention are oils of lubricating viscosity derived from petroleum or synthetic 4 sources. The oils may be paraffinic, naphthenic, asphaltic or combinations thereof. Oils of lubricating viscosity normally have viscosities in the range of 35 to 50,000 Saybolt Universal Seconds (SUS) at F., more usually from about 50 to 10,000 SUS at 100 F.

Other additives Other additives are desirably included in the composition. These additives may be pour point depressants, oiliness agents, antioxidants, detergents, particularly succinimides, supra, corrosion inhibitors, extreme pressure agents, etc. Usually, for oils to be used in an engine, the total amount of these additives will range from about 0.1 to 15 weight percent, more usually from about 0.5 to 10 weight percent. The individual additives may vary in amount from about 0.01 to 10 weight percent of the total composition. In concentrates, the weight percent of these additives will usual-1y range from about 0.3 to 30 weight percent.

A preferred aspect of using the compositions of this invention in lubricating oils is to include in the oil from about 1 to 50 mM./kg. of a dihydrocarbyl phosphorodithioate, wherein the hydrocarbyl groups are from about 4 to 36 carbon atoms. Usually, the hydrocarbyl groups will be alkyl or alkaryl groups. The remaining valence of the phosphorodithioate will usually be satisfied by zinc, but polyalkyleneoxy or a third hydrocarbyl group may also be used. (Hydrocarbyl is an organic radical composed solely of carbon and hydrogen which may be aliphatic, alicyclic or aromatic. In this invention, the preferred hydrocarbyl groups are free of aliphatic unsaturation.)

EXAMPLES A number of lubricating oil compositions were prepared by combining the appropriate amount of alkaline earth metal carbonates, specifically calcium carbonate, dispersed by either a sulfonate or a phenate with N-octadecyl (derived from tallow fatty acids) N,N',N'-tri(2-hydroxyethyl) propylene diamine. (Supplied by Armour & Co. as Ethoduomeen T-13; the composition also contains about 30% :by weight of the total composition of N-octadecyl [derived from tallow fatty acid] N,N-di(2-hydroxyethyl) amine.) These compositions were tested in a variety of tests to establish their eifectiveness as rust and corrosion inhibitors. The following indicates the tests carried out, the comopsitions employed, and the results of these tests.

The first test is carried out as follows: A GM Oldsmobile oil relief valve (cut lengthwise into halves) is polished with No. 2/0 emery polishing paper, rinsed with CF. hexane and then stored in hexane. The relief valve is then placed in 100 ml. of test oil heated in a beaker at -130 F. for one minute. An acidic solution is provided by combining 9 ml. of a solution prepared from 4 ml. of concentrated hydrochloric acid, 4 ml. of glacial acetic acid, 4 ml. concentrated sulfuric acid and 84 ml. distilled Water with 300 ml. of test oil in a 400 ml. beaker. After stirring at 2000 r.p.m. for 8 minutes, the acid solution and test oil composition are placed in an oil bath maintained at F. The treated relief valve is then put into the oil mixture with the flat surface sitting on the bottom of the breaker. After stirring at 550 r.p.m. for 20 hours, the beaker is removed from the oil bath, the valve removed from the oil and rinsed twice with C.P. hexane and rated. The valve is rated from 0 to 10; 0 equaling heavy rust and 10 being clean.

The test oil employed, simulating a commercially compounded oil, was an SAE 30 oil (26.7 wt. percent 130 neutral oil, 42.8 wt. percent 480 neutral oil and 30.5 wt. percent bright stock; this was the base oil in all the tests unless otherwise indicated) containing 2 weight percent of a polyisobutenyl succinimide of tetraethylene pentamine (the polyisobutenyl group having a number average molecular weight of about 1000), 12 mM./ kg. of zinc dialkyl dithiophosphate (alkyl of from 4 to 5 carbon atoms) and 40 mM./kg. based on Ca. of calcium carbonate dispersed with calcium mahogany sulfonate wherein the base ratio is 9.3, and the calcium carbonate composition contains 11.4% calcium. The final composition has an alkalinity value from the calcium carbonate of about 1.45.

The rust rating for the reference oil without the diamine was 6.5. With 0.3 weight percent of the diamine and 0.15 weight percent of the monoamine, the rust rating was 9.1 and 9.4.

The next tests which were employed are called the Humidity Cabinet Test and the Hydrobromic Acid Panel Rust Test. The Humidity Cabinet Test is ASTM D1748 and employs a sand blasted steel panel /8" x 2" x 4" dipped in the oil to be tested, drained of free oil at room temperature and placed in the humidity cabinet at 120 F. and 100 humidity for the time specified for the results. The HBr test employs 3 sand blasted steel panels of the same size as above immersed for no more than 1 second in 0.1% aqueous hydrobromic acid. Within one second of removing the test panels from the hydrobromic acid solution, the test panels are dipped in the oil to be evaluated at room temperature. The test panels are dipped and removed from the test oil 12 times during a period of 60 seconds, after which they are suspended in air for 4 hours at room temperature and then examined for rusting. The results are compared with a commercially available rust inhibitor, tetrapropenyl succinic acid.

l Reference oil-In the base oil was included 2 wt. percent polyisobutenyl succinimide of tetraethylene pentamine (polyisobutenyl ot- 1,000 number average molecular weight); 12 mM./kg. of zinc dialkyl dithiophosphate (alkyl of from 4 to 5 carbon atoms); 40 mM./kg. based on Ca of calcium mahogany sulfonate overbesed with calcium carbonate (9.31 base ratio; 11.4 wt. percent Ca); and 0.02 wt. percent terephthalie aci 0.35 wt. percent -N,N,N'-tri(2-hydroxyethyl) Noctadecyl propylene diamine and 0.15 wt. percent of N -octadecy1 diethanolamine.

a Duplicate runs.

The next series of tests is the MS Sequence Engine Test. This test is part of the GM specifications and requires a rating of 9 per pass. The first test was carried out using the same reference oil as employed in the Half Relief Valve Rust Test and the same amine composition as employed in that test. The average rust rating for the reference formulation was 8.4 and 8.8. The reference formulation with the amine had an average rust rating of 9.2.

The MS Sequence IIB Engine Test was repeated using a mid-continent 10W base oil containing 1.9 weight percent of the same succinimide employed previously, 6.25 mM./'kg. of zinc dialkylphenyl dithiophosphate (alkyl is polypropenyl of from 12 to 15 carbon atoms), 9.25 mM./kg. of zinc dialkyl dithiophosphate (alkyl is from 4 to 5' carbon atoms) plus the additional additives set forth in the following table:

1 Sulionate-Calcium mahogany sultonate and calcium carbonate having a 9.3 base ratio, 11.4 wt. percent Ca.

2 N-octadeeyl (derived from tallow fatty acid) N N N tri(2hydroxyethyl) propylene diamine. Additionally, there is .15 wt. percent of N-octadecyl (derived from tallow fatty acid) dicthanolamine.

3 Calcium carbonate dispersed calcium polypropylene phenate (polypropylene of from 12 to 15 carbon atoms) 9.25 Wt. percent Ca, mol ratio of CaCO; to phenoxide is about 1.5-2.1.

4 The alkalinity value derived from the overbased sulfonate is 1.45 mg.

KOH/g.

5 Ellie alkalinity value derived from the overbased sulionate is 2.9 mg. KO

Th allralinity value from the overbased phenate is 4.45 mg. KOH/g.

1 The alkalinity value from the overbased phenate is 8.9 mg. KOH/g. The above results demonstrate that the combination of alkaline earth metal carbonate and the poly(hydroxyalkylated) alkyl amines provide excellent rust protection, not only under the conditions of recognized bench tests, but also under the severe conditions of the MS Sequence IIB Engine Test. Furthermore, the amine composition combination with alkaline earth metal carbonate provides a pass under the very rigid specifications set forth by General Motors. In addition, the use of the amine compositions permits smaller amounts of ash to be introduced into the oil and therefore avoids the problems associated with high ash oils. Finally, the hydroxyalkylated amine compositions are compatible with a wide range of other lubricating oil additives providing clear bright lubricant V compositions.

What is claimed is:

1. A hydrocarbon lubricating oil composition comprising a major amount of a hydrocarbon oil of lubricating oil viscosity, from 0.05 weight percent to about 3 weight percent of a compound of the formula:

wherein a is 0 or 1;

R is an aliphatic hydrocarbon group of from 12 to 24 carbon atoms; and

U and Y are each alkylene of from 2 to 3 carbon atoms; and sufiicient alkaline earth metal carbonate dispersed in said hydrocarbon oil as an overbased phenate or sulfonate to provide an alkalinity value of from 0.5 to mg. KOH/g.

2. A composition according to claim 1 wherein R is of from 16 to 18 carbon atoms, U is ethylene and Y is propylene.

3. A composition according to claim 1 wherein said alkaline earth metal carbonate is calcium carbonate dispersed in said oil with a phenate or sulfonate lubricating oil dispersant.

4. A composition according to claim 3 wherein said dispersant is a sulfonate dispersant derived from a sulfonic acid of from 25 to 50 carbon atoms.

5. A composition according to claim 3 wherein said dispersant is a phenate derived from alkylated phenol or polymerized alkylated phenols having from 2 to 5 phenol groups per molecule and an alkyl group of from 12 to 30 carbon atoms.

6. A hydrocarbon lubricating oil composition comprising a major amount of a hydrocarbon oil of lubricating oil viscosity, from 0.1 to 2 weight percent of N-aliphatic hydrocarbon substituted amine or N-aliphatic hydrocarbon substituted propylene diamine, wherein the aliphatic hydrocarbon group is of from 16 to 18 carbon atoms and the valences of the amine nitrogen atoms bonded to other than the aliphatic hydrocarbon group or the propylene group are bonded to Z-hydroxyethyl groups; and sufficient calcium carbonate dispersed in said hydrocarbon oil as an overbased phenate or sulfonate to provide an alkalinity value of from about 1 to 20 mg. KOH/ g.

7. A composition according to claim 6 wherein said calcium carbonate is dispersed with a hydrocarbon suifonate having from 25 to 50 carbon atoms per sulfonic acid group.

8. A composition according to claim 6 wherein said calcium carbonate is dispersed by a phenate having from 1 to 5 alkyl phenol groups per molecule and wherein the alkyl group is of from 8 to 36 carbon atoms.

References Cited UNITED STATES PATENTS 3,488,284 1/1970 Le Suer et a1 25233 8 10/ 1961 Fefer 25233.4 8/1967 .Allphin 25233.4 12/1967 Stambaugh 25233.4 2/ 1968 Retzlotf et a1 25233.4 9/ 19-70 Dadura et a1. 252--42.7 2/ 1957 Cafcas 25234.7 X 11/1962 Manteuifel et a1. 252-5 1.5 R 6/1966 Wiese 252 495 X 9/1970 Pellaton 25233.4 X

OTHER REFERENCES J. W. McCutcheon, Detergents and Emulsifiers, 1963,

5 DANIEL -E. WYMAN, Primary Examiner W. J. SHINE, Assistant Examiner 4/1967 Le Suer et a1 25233 20 US. Cl. X.R. 

